a star destroyer is a powerful spaceship that can range from 2 to 5 kilomters long depending on class, the highest class, a super star destroyer has so much stuff packed into it is a fleet all by itself, a full super star destroyer or ssd is complaimented with over 250,000 cew members, and packs several squardens of fighters dozens of at-ats and at-sts, only a handful od ssds have ever been produced, there are three facts they are know about the ssd...
1.it's the best ship ever invented, you would want one.
2.vader had one.
3.it kicks butt.

commder-guy: command all star destroyers to fire upon each other.
yes-sir-guy: yes, sir. right away.

the greatest star ship ever invented for any movie. it's flight over the camera at the very beginning of star wars episode 4 remains one of the greatest achievements in cinematic wonder ever. only eclipsed by the super star destroyer that first appeared in episode five.

Space battleship of the Imperial Starfleet in Star Wars. Has multiple banks of turboblasters for ship to ship combat and planetary bombardment. Has banks of Ion Cannons for long range ship to ship warfare.

Various classes of Imperial warships, ranging from 900 meters up to 17,000 kilometers. Introduced during Clone Wars, the original ship was the Victory-class. The Venerators then were used, and fought with distinction in the Second Battle of Coruscant (Clone Wars). Then the Imperators replaced the Venators after the Clone Wars, with these warships being scrapped to make the Imperators, or relegated to Outer Rim duty in the Empire. Victory-IIs were introduced around this time. The Imperators have 2 subclasses, the Imperator-Is and Imperator-IIs. Then there are the Executor-classes. These "Super Star Destroyers" anything larger than Imperators are 17,600 meters. These are dwarfed by the Sovereign-classes, which are only 15 km lon, but much thicker and the largest Star Destroyer, the Eclipse-class.